Current Use of Noninvasive Hemoglobin Monitoring in Anesthesia

Modern technology enables clinicians to assess hemoglobin levels noninvasively and continuously. Some instruments also provide concentrations of other types of hemoglobin, such as methemoglobin and carboxyhemoglobin. Such information obtained immediately and noninvasively can be helpful in the management of critically ill patients or those undergoing surgery with bleeding. However, the accuracy of noninvasive hemoglobin measurements should be evaluated before clinical application, particularly for transfusion decisions. Clinicians should be aware of the performance of continuous noninvasive hemoglobin monitoring devices during anesthesia and of the various factors that influence their accuracy. This review considers the accuracy of current continuous noninvasive hemoglobin monitoring and its clinical use.